weibulltools (version 1.0.1)

nelson_method: Estimation of Failure Probabilities using the Nelson-Aalen Estimator

Description

This non-parametric approach estimates the cumulative hazard rate in terms of (multiple) right censored data. By equating the definition of the hazard rate with the hazard rate according to Nelson-Aalen one can calculate the failure probabilities. Since the failure probability estimation in this function is not based on Median Ranks, the Betabinomial confidence intervals cannot be calculated on the basis of Nelson-Aalen failure probabilities.

Usage

nelson_method(x, event, id = rep("XXXXXX", length(x)))

Arguments

x

a numeric vector which consists of lifetime data. Lifetime data could be every characteristic influencing the reliability of a product, e.g. operating time (days/months in service), mileage (km, miles), load cycles.

event

a vector of binary data (0 or 1) indicating whether unit i is a right censored observation (= 0) or a failure (= 1).

id

a character vector for the identification of every unit.

Value

A data frame containing id, lifetime characteristic, status of the unit and the estimated failure probabilty. For right censored observations the cells of probability column are filled with NA.

Examples

# NOT RUN {
obs   <- seq(10000, 100000, 10000)
state <- c(0, 1, 1, 0, 0, 0, 1, 0, 1, 0)
uic   <- c("3435", "1203", "958X", "XX71", "abcd", "tz46",
           "fl29", "AX23","Uy12", "kl1a")

df_nel <- nelson_method(x = obs, event = state, id = uic)

# }